Interest Rate Expectations: How Does Inflation Affect the Pound?

Inflation affects the pound mainly through what markets expect the Bank of England to do about it: if higher inflation makes rate rises more likely, sterling tends to strengthen because UK assets offer better returns. That is what happened in October 2026. UK consumer price inflation rose to 3.5% in the year to September, squeezing household incomes, yet the pound gained as traders priced in tighter policy.

What Did the September 2026 Inflation Data Show?

According to the ONS, CPI inflation rose to 3.5% in September 2026, up from 3.1% in August. The largest upward contribution came from transport, particularly motor fuels, whose prices were 29.8% higher than a year earlier. Petrol averaged 169.5p a litre, the highest price recorded since August 2022.

A rise in fuel prices is a textbook example of cost-push inflation, driven by higher production costs rather than excess demand. Central banks often look through such shocks.

The more important detail lay beneath the headline. Core inflation, which excludes energy, food, alcohol and tobacco, rose from 2.6% to 2.8%, while services inflation climbed from 3.4% to 3.7%. Services prices are closely linked to wages, so they are a guide to how persistent inflation is likely to be.

Why Can Higher Inflation Strengthen the Pound?

In the short term, exchange rates respond less to inflation itself than to expected interest rates. Higher expected rates make sterling deposits and UK government bonds, known as gilts, more attractive. Foreign investors who want those returns must first buy pounds, which raises demand for the currency.

Traders following GBP/USD or EUR/GBP on TradingView would have seen this play out after the release, as sterling firmed against both the dollar and the euro.

Reuters reported on 21 October that sterling was trading at around $1.339, near a one-month high, and was close to 2% stronger against the euro so far that month. Money markets were almost fully pricing a quarter-point rate rise in November.

How Do Interest Rate Differentials Affect Currencies?

What matters most is the gap between UK interest rates and those elsewhere. When UK rates are expected to rise faster than rates in the euro area or the US, the return on holding sterling improves relative to other currencies.

A wider gap encourages the carry trade. An investor borrows in a lower-yielding currency, converts it into a higher-yielding one and earns the difference in interest, provided the exchange rate does not move sharply against them. Flows of this kind can push a currency up for as long as the rate gap is expected to last, but they can reverse quickly if expectations change.

When Does Inflation Weaken a Currency?

Higher inflation does not reliably support a currency. Over longer periods, purchasing power parity suggests that a country with persistently higher inflation should see its currency depreciate, because its goods become less competitive abroad.

Credibility also matters. In September 2022, with UK inflation heading towards a peak of 11.1%, sterling fell to a record low of about $1.03 after the government’s unfunded mini-budget. Investors doubted that fiscal and monetary policy were working together. Inflation paired with a central bank willing to act is very different from inflation paired with policy confusion.

Real interest rates add a further test. With Bank Rate at 3.75% and inflation at 3.5%, the real policy rate is only just positive. If prices rise faster than interest rates, that small cushion disappears.

What Do Markets Expect From the Bank of England?

Bank Rate has been 3.75% since December 2025. In September 2026, the Monetary Policy Committee voted 6-3 to hold it, with Megan Greene, Catherine Mann and Huw Pill voting for a rise to 4%. The minutes noted that CPI inflation could now reach slightly over 4% in early 2027.

The September figures strengthen the case made by the three members who voted to raise rates. The important consideration for everyone else is whether the increased costs of energy are flowing through to wage rates and the costs of services. These second-round impacts are responsible for converting a short-term shock into longer-term inflation.

Fiscal policy is the other variable. Chancellor John Healey’s first budget, delivered on 28 October, was received calmly. According to Reuters, gilt yield prices fell slightly, and the GBP/USD was virtually unchanged, indicating there was no significant mix of new views placed on the bank by the investors.

What Is the Bigger Picture for Sterling?

Sterling’s recent strength shows how expectations move markets. The pound did not rise because of inflation alone but because investors concluded that the Bank of England was likely to respond. That relationship can reverse. Weaker growth, a softer message from the Monetary Policy Committee or new doubts about the public finances could turn the same inflation data into a drag on the currency.